Highlights

Since 1989, the U.S. Global Change Research Program (USGCRP) has submitted annual reports to Congress called Our Changing Planet. The reports describe the status of USGCRP research activities, provide progress updates, and document recent accomplishments.

In particular, Our Changing Planet highlights progress and accomplishments in interagency activities. These highlights represent the broad spectrum of USGCRP activities that extend from Earth system observations, modeling, and fundamental research through synthesis and assessment, decision support, education, and public engagement.

Methane emitted from thawing permafrost below an Arctic thermokarst lake is trapped in bubbles of many different sizes and shapes as the ice grows during the winter.

Long-frozen northern soils known as permafrost contain one of the world’s largest stores of organic carbon. This reservoir is stable while soils are frozen, but as permafrost thaws, decomposition of biomass by microbes produces the heat-trapping gases carbon dioxide and methane, returning soil carbon to the atmosphere where it contributes to climate change. Permafrost carbon stores are expected to be increasingly vulnerable to decomposition as the climate continues to change, leading to a feedback cycle of further warming and permafrost thaw.^[1]...

Map shows the average active layer thickness (ALT) at the end of the growing season for the Barrow, Alaska region that contains the NGEE Arctic study site.

Scientists are gaining new understanding of processes that control greenhouse gas emissions from Arctic permafrost, a potential driver of significant future warming.

Rapid warming in the Arctic is causing carbon-rich soils known as permafrost, previously frozen for millennia, to thaw. As thawing soils decompose, the greenhouse gases carbon dioxide and methane are released into the atmosphere in varying proportions depending on the conditions under which decomposition occurs. Permafrost emissions could contribute significantly to future warming...

AmeriFlux FLUXNET2015 data collection sites overlaid on a map of global land cover types.

A global data collection network has built a strong foundation for carbon cycle understanding.

The AmeriFlux Network, which is supported by the Department of Energy, connects scientists from across the Western Hemisphere studying the exchange of carbon, water, and energy between ecosystems and the atmosphere. Since its launch in 1996, AmeriFlux has built a data record from 213 sites worldwide, called...

Modeling Permafrost Response to Climate Change

Vast quantities of carbon—twice the size of the current amount in the atmosphere—are stored in frozen permafrost soils in Arctic regions. The Arctic climate is warming much more rapidly than the global average, leaving these carbon pools highly vulnerable to release into the atmosphere as carbon dioxide and methane as soils thaw and decompose, leading to a feedback cycle of further warming and increasing carbon release. The potential for these carbon stocks to increase global-warming rates, and the rapid changes already observed in the permafrost region, have captured the attention of...

Improving Predictions of Changing Arctic Ecosystems

A key challenge for Earth System Models is accurately representing land surface and subsurface processes and their complex interactions in a warming climate. This is true for ecosystems across the globe, but particularly critical for Arctic ecosystems, which are projected to warm at a rate twice that of the global average by the end of the 21st century. The Next-Generation Ecosystem Experiments in the Arctic (NGEE-Arctic) project is addressing this challenge by integrating process studies, ecosystem observations, and computational...

Tracking Methane Emissions from Arctic Tundra

The Arctic tundra is a cold, desert-like biome, with a layer of permanently frozen soil and organic matter below the surface containing vast stocks of carbon. As Arctic tundra soils warm in response to climate change, methane emissions from decomposing organic material could increase dramatically, representing a potentially significant positive feedback on climate warming. However, seasonal and climatic influences on methane emissions from these systems are not well understood outside of the summer months, representing a major uncertainty for the Arctic methane budget. To help address a...

The carbon cycle—or the continual flux of carbon through the atmosphere, oceans, soil, and living organisms—is a foundational component of the Earth system that interacts with climate change and human activities. Through USGCRP and its U.S. Carbon Cycle Science Program, Federal agencies are working together and with the scientific community to advance fundamental and applied research in this critical field. Some examples are highlighted below:

In 2014, NASA, USDA, DOE, and NOAA

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Inside the prototype for SPRUCE experimental chambers. (Credit: DOE)

The continual cycling of carbon through the atmosphere, oceans, soil, and living organisms is an essential function of the Earth system. The U.S. Carbon Cycle Science Program (under the auspices of USGCRP; carboncyclescience.us) and USGCRP agencies are working to understand how climate change and human activities are altering this foundational component of the environment, and how these alterations feed back to affect climate change. Some examples are highlighted below:

At least two thirds of the world’s land-based organic carbon is stored in

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Highlights

Scientists investigate the effects of carbon emissions from thawing permafrost soils

Understanding carbon cycling in Arctic ecosystems

Supporting twenty years of carbon cycle understanding

Modeling Permafrost Response to Climate Change

Improving Predictions of Changing Arctic Ecosystems

Tracking Methane Emissions from Arctic Tundra

Carbon Community Collaboration

Carbon Cycle Science for a Changing World